Metal transfer and pouring system



April 4, 5 w. H. FINKELDEY ET AL 2,549,790

METAL TRANSFER AND POURING SYSTEM Filed June 11, 1948 2 Sheets-Sheet l Filed June 11, 1948 2 Sheets-Sheet 2 April 24, 1951 w. H. FINKELDEYY ETAL .v :2 2,549,790

METAL TRANSFER AND POURiNG SYSTEM By W v jffof/l/f/ Patented Apr. 24, 1951 TENT OFFICE METAL TRANSFER AND POURING SYSTEM William H. Finkeldey, Hastings on Hudson, N. Y.,

and Fletcher R. Edes, Plymouth, Mass, assignors to Singmaster & Breyer, New York, N. Y.,

a copartnership Application June 11, 1948, Serial No. 32,286

Claims.

This invention relates to a system, including methods and apparatus, for transferring and pouring molten metal from a crucible or similar supply reservoir to molds or other receptacles,

ficiently than heretofore, with less trouble from dross, and with any desired periods of continuation or interruption of the operations.

There have been several proposals prior to our invention for the utilization of a siphon in transferring molten metal from a supply bath, but as far as we are aware they have had little or no practical usefulness under conditions like those encountered in casting zinc. They involve serious operating faults, in that the siphon takes in air and requires re-priming after each occasion of feeding the metal; the desired regularity of feeding is interfered with by air bubbles in the siphon, for which there has been no satisfactory remedy; the tube becomes obstructed by adhesions of dross or metal; or the tube material is eroded by the molten metal, especially in the case of zinc.

Accordingly, the transfer and pouring of molten zinc and the like from supply baths or crucibles to slab molds is still accomplished by hand operation with the use of ladles carried to mold stands.

Needs have long existed for a practical system for performing much of this work mechanically and yet retaining full control or flexibility of the actual casting operations so that they may proceed with any desired periods of continuity or discontinuity. Furthermore, the art of casting slab zinc or the like has long needed a way of reducing or eliminating troubles that result from the dross on the surface of the molten metal.

The principal object of this invention is to provide a system that fulfill the needs just described.

A further object is to enable the successful and efficient utilization of a siphon for this purpose and, more particularly, to bring about the transfer and pouring of molten zinc or the like through siphon action without encountering the above-mentioned operating faults of known siphon transfer systems.

Another object of the invention is to provide a metal transfer and pouring system whereby molten metal is poured under manual control in any desired manner from a suitable container such as a ladle into molds, while the metal thus cast is replaced automatically from a crucible or other supply reservoir so that the ladle is always ready for pouring and so that manual attention is required, at most, only for manipulation of the ladle.

Another object is to provide a system for transferring and casting molten zinc or other easily oxidizable metal by which the formation of dross and difficulties arising from its presence are reduced to an important extent.

Still another object of this invention is to provide for the casting of zinc or other molten metal into a succession of many individual molds with greater speed and efiiciency than have been practicable heretofore.

The foregoing and other objects, features and advantages of this invention will be apparent from the following description and from the accompanying drawings of a preferred embodiment, it being understood that the detailed description and drawings are merely illustrative of the invention which is defined in the claims.

In the drawings,

Fig. 1 is a front elevation partly broken away and partly in section, as viewed approximately along line l-l of Fig. 2, of a metal transfer and pouring system embodying this invention in use for delivering molten zinc from a melting furnace through a siphon and a ladle into a series of slab molds.

Fig. 2 is an end view, partly broken away, of the assembly shown in Fig. 1;

Figs 3a and 3b are diagrammatic views showing the upright or non-pouring position and the pouring position, respectively, of the ladle with respect to the siphon tube and a mold at the casting station;

Fig. 4 is a fragmentary vertical section showing the first step in priming the siphon, the siphon tube being shown for clarity without its enclosing jacket;

Figs. 5, 6, and 7 are views similar to Fig. 4 which show, respectively, the intermediate and final stages in the siphon priming ope-ration and the working position of the primed siphon with respect to the supply bath and the ladle; and

Fig. 8 is a vertical section showing the siphon tube assembled. with its enclosing jacket and with its ends inserted into electrically heated boots, as it is conditioned for use or held between use periods.

According to this invention, as seen in Figs 1 and 2, molten zinc or similar metal to be processed is transferred through a siphon device I from a supply bath 2 of the metal held, for example, in a crucible 3 of a melting pot or furnace l, to a separate body of the metal in a ladle 6 spaced horizontally away from the bath at a casting station; and the metal is poured from the ladle 6, whenever and as long as desired, so as to fill successively each of a number of slab molds 1. The molds may be carried to the casting station by a conveyor, for example, a rotary casting table 8. Whether the pouring be continuous or discontinuous, as long as the supply bath 2 remains at a suitable level in the crucible 3 the molten body 5 in the ladle is automatically replenished as metal is poured from it by transfer of metal from the bath 2 through the siphon device in the manner more fully explained below. Thus, in effect, the present system provides a ladle that pours metal either continuously or intermittently without ever emptying.

The principal element of the siphon device is a tube 9 (Figs. 4 to '1), generally U-shaped, which is inverted so that a longer leg It extends downwardly into the metal bath 2 while the other leg H extends downwardly into the body 5 of molten metal in ladle 6. Thus the intake and discharge ends of the siphon are both immersed in molten bodies of the metal so that they open into these bodies well below any layers of dross On them, and when the siphon is active it automatically transfers metal free of dross from the supply bath into the ladle 6 without exposing the metal to oxidation by the atmosphere.

The siphon tube 9 having been primed so as to be entirely full of metal, it will be evident that the surface of the body of metal in laddle 5 normally assumes the same level as that of the supply bath 2. The ladle here shown, which is the preferred but not the only useful form, is a tilting ladle swingable on a horizontal axis, for example that of trunnions 14, from an upright position in which the lip of the pourning spout l3 lies above the level of the bath 2 to a pouring position in which said lip lies below that level. The discharge end 2 of the siphon tube is immerse'd in the ladle metal 5 to a level below either position of the pouring lip, as seen in Figs. 3c and 3b. Accordingly, the pouring of metal from the ladle occurs without ever uncovering the immersed discharge end of the siphon or exposing it to the atmosphere, and the system continues operative throughout pouring operations and interruptions thereof of any desired duration, without requiring any repriming of the siphon after it has been once filled at the outset of operations.

When the ladle is tilted to the pouring position, as seen in Fig. 3b, metal flows from it into a -mold and the metal thus cast is immediately replaced through the siphon to maintain a substantially constant body of metal in the ladle. Furthermore, in the casting of zinc or other dross forming metal the pouring generally occurs from beneath the layer of dross formed at the surface of body 5, so that a minimum of dross passes to the slab cast in the mold. When the ladle is moved back to its upright position the metal body 5 immediately resumes its normal level corresponding to the level of bath whereupon the siphon action discontinues automatically so that the metal never overflows the upright ladle. The siphon, nevertheless, remains ready for further action in immediate response to a further movement of the ladle to its pouring position.

'It has been found that particularly effective operations can be obtained according to this invention by the use of a siphon tube 9 formed as a continuously unbroken tube of non-porous ceramic or glazed material such as a fused porcelain, fused silica or glass, i. e., a tube entirely free of joints, crevices and valves and made, preferably, of a glass such as Pyrex glass that resists heat at the temperature of the molten metal being transferred. Such a siphon tube can give long service without fracturing; the molten metal easily flow through it; its freedom from pores, joints or other crevices accessible to air assures a full and uniform siphon action as long as desired; and the tube is not eroded by the molten metal or its dross.

In order to prevent adhesions of metal or dross in the tube, or to prevent thermal shocks that might fracture it in the use of a glazed tube, it is important to preheat the tube to a point near the temperature of the molten metal before assembling and priming the tube with the metal. Further, the exterior of the tube should be heated at a like temperature during the pouring operations, especially if long intervals may occur between pouring steps. A structure particularly effective for these purposes can be obtained, as shown in Fig. 8, by enclosing substantially all of the tube except the end portions of its legs ill and ii within a jacket l5, made of sheet steel or other suitable sheet material, which contains electrical radiant heating elements It arranged to heat the exterior of the tube to the desired temperature. The exposed end portions of the legs [5 and II are heated similarly in preparing the tube for use, or during periods of disuse of the system, by inserting them into boots or housings l! which carry electrical radiant heating elements I8 arranged to heat these end portions. During periods of use of the system the exposed end portions are kept heated at a uniform temperature by their immersion in molten metal.

It is evident from the foregoing description that the siphon tube 9 must be primed, i. e., completely filled with the molten metal, at the outset of use of the system. This can be accomplished quickly and efficiently notwithstanding the (ii-J- culty of access to the interior of the siphon when using a continuously unbroken tube, in the manner illustrated in Fig. l and Figs. 4 to '7 of the drawings. As shown in Fig. 1, the siphon device I is assembled in working position with its main body disposed horizontally but susceptible to tilting movement in a vertical plane. For example, the device may be suspended by chains 28 and 2! connected to jacket l5 and converging to a common swivel suspension point 2'2. Figs. 4 to '7 omit illustration of the jacket and the suspending means for clarity in showing the siphon tube 9. As seen in Fig. 4, when the siphon tube is first placed in working position, a small bendable suction tube 24 of copper or other suitable material has been inserted through the intake leg l6 until the end 25 of the suction tube lies at a high point of the siphon at the curve of leg ill. The suction tube extends from the end of leg ii) in the metal bath '2 out of the bath to a point of connection to a vacuum line 2% controlled by a valve 2'5. The discharge end id of the siphon tube is immersed in'a body 5 of the molten metal previously placed in the ladle 6, so that both ends of the siphon tube are immersed.

In the next stage of the priming, as seen in Fig. 5, the siphon tube 9 is tilted slightly so that the location of its high point orapex at end '25 of the suction tube is definitely assured, and then the vacuum valve 21 is opened to apply strong suction through the minute passageway in the suction tube. The air in tube 9 is immediately drawn out through the suction tube, and molten metal enters the siphon from bath 2 and body 5. The entering metal approaches end 25 of the suction tube as seen in Fig. 5, and then, as the last air is evacuated, the siphon tube'becomes completely filled as seen in Fig. 6. Some of the molten metal is even drawn into the suction tube 24, but this action is immediately stopped, with automatic stoppage of the suction, because the metal passing through the minute passageway of the suction tube freezes in it before reaching the vacuum line 26. Thereupon, valve 21 is closed, the suction tube 24 is removed by pulling or bending it out of the intake leg Hi, and the siphon device assumes its normal working position shown in Figs. 1, 2 and '7.

According to a further feature of the present invention, the discharge end of the siphon device I and the ladle 6 are mounted for movement in a horizontal path along the path of movement of molds on the conveyor or casting table 8, and means are provided for moving the ladle in synchronism with the conveyor during the casting period required for the filling of each mold on the conveyor.

As seen in Figs. 1 and 2, for example, the suspension of siphon device I b chains 28 and 2| from point 22 not only lets the siphon tilt in a vertical plane for the priming operation but also permits it to swing in a horizontal path. The ladle 6 also is supported for horizontal movement, its trunnions 14 being carried in hubs Bil on arms such as 3| that extend upward and then inward to a common hanger 32 suspended from a mono-rail track 33. The hanger and ladle assembly is movable along this track, which has a path paralleling that of the casting table 3 as indicated by broken line 34 in Fig. 2.

One of the ladle trunnions M has an extension forming a shaft 35 equipped with handle bars 36 by which an operator tilts the ladle to and from its pouring position. A rod 31 extends radially from this shaft and has an end 38 which, in the pouring position of the ladle, lies in the path of movement of a, part of the casting table 8, for example, in the path of one of the angle iron supports 3%: and 391) which hold each mold I on the casting table. In the upright position of the ladle the rod end 38 lies outside the path of the casting table. The spacing between the ladle pouring lip l3 and the end 38 of rod 31 is such that when the latter is engaged by a mold support 39a the ladle is located properly for pouring into the mold carried by that support.

Accordingly, the system may be operated efficiently as follows, in casting successively into each of many individual molds on a continuously rotating casting table 8. When a mold 1 moves beneath the ladle lip 13 at the casting station the operator simply tilts the ladle to its pouring position by the handle bars 36 and holds the ladle tilted until the mold is filled. Meanwhile, the mold support 39a abuts and moves the rod end 38 with table 3, and this produces a like movement of the ladle 6, and also of the siphon if necessary, along the path of the mold being filled. When the casting in this mold is complete, the operator simply tilts the ladle back to its upright position and pushe it horizontally back to its starting point, where the next mold on the casting table is soon ready to be filled in the same manner.

We claim:

1. In a method of transferring and casting molten metal, the steps which comprise inserting through one end of a continuously unbroken siphon tube to a high point therewithin a suction tube having a minute suction passageway, then immersing the-ends of the siphon tube, respectively, in a bath of the metal and a separate horizontally aligned body of the metal in a ladle, said suction tube then extending from said one end out of the metal in which that end is immersed, evacuating air from the siphon tube through said suction tube so as completely to fill the siphon tube with the metal, then extracting the suction tube.

2. A method of transferring and casting molten metal which comprises providing a crucible with a supply bath of the metal and in horizontal alignment therewith providing a ladle with a body of the metal, immersing the ends of a continuously unbroken U-shaped siphon tube, respectively, in said bath and said body and suspending the base of the tube thereabove for horizontal movement, then completely evacuating air from the tube so as to fill it completely with the metal and establish siphon action between said bath and said body, moving molds successively in a horizontal path through a casting position adjacent the spout of the ladle pouring metal from the ladle into said molds successively by moving the ladle spout between levels above and below the surface of said bath, maintaining said tube ends immersed below the lower spout level throughout the pouring operations and interruptions thereof so that siphon connection is maintained between the bath and said body, and while pouring into each mold moving the ladle and the end of said tube therein with and along the path of the mold.

3. In a method as described in claim 2, employing as said siphon tube a continuously unbroken tube of glass that resists heat at the temperature of the molten metal, heating said tube prior to said immersion to a point near said term perature, and continuing so to heat the exterior of said tube during the pouring period.

4. In a method of transferring and casting molten metal, the steps Which comprise inserting through one end of a continuously unbroken U -shaped siphon tube to a high point therewithin a long bendable suction tube having a minute suction passageway, then immersing the ends of the siphon tube, respectively, in a bath of the metal and a separate horizontally aligned body of the metal in a ladle, the suction tube then extending from said one end out of the metal in which that end is immersed, then evacuating air from the siphon tube through said suction tube so as completely to fill the siphon tube with the metal, then extracting the suction tube by pulling and bending it out of the filled siphon tube.

5. In molten metal transferring and casting apparatus comprising a reservoir to hold a supply bath of metal and a horizontally aligned ladle to hold a body of the metal, a continuously unbroken U-shaped siphon tube to extend between said reservoir and said ladle and open only at its leg ends, means for suspending said tube in working position over and with its legs immersed, respectively, in said bath and said body, means for carrying molds to and from a casting position below the spout of said ladle, means for moving the ladle to pour metal directly from said body into a mold at said position, the leg of the tube in the ladle extending below said spout at the idle and the pouring positions of said ladle, and means supporting said ladle for movement horizontally along the mold path, the tube being swingable horizontally on its suspending means so that the leg in the ladle follows horizontal movements of the ladle.

6. Apparatus as described in claim 5, said siphon tube being composed of Pyrex glass,

'7. In a molten metal transferring and casting apparatus comprising a reservoir for a supply bath of the metal, a horizontally aligned ladle supported for horizontal and tilting movements to pour the metal, a continuously unbroken inverted U-shaped siphon tube to interconnect said bath and a body of the metal held in said ladle, all except end portions of said tube enclosed within a jacket carrying heating elements to heat said tube, and means connected with said jacket for suspending said tube in working position over and with said end portions extending, respectively, into said bath and said body, the tube being freely swingable on said suspending means so that the end portion in said ladle follows horizontal movements of the ladle.

8. In a molten metal transferring and casting apparatus comprising a reservoir for a supply bath of the metal, a ladle to hold a body of the metal and a continuously moved conveyor to carry molds successively to and from a casting position at the ladle, an inverted U-shaped siphon tube to interconnect said bath and said body, means for suspending said tube in working position over and with its ends immersed, respectively, in said bath and said body, means mounting said ladle in horizontal alignment with said reservoir and for movement along the path of said conveyor, said suspending means holding the tube swingably so that the end of said tube in said body is movable with the ladle along said path, means for moving said ladle toward said conveyor to pour metal into a mold thereon, and means moved by conveyor when the ladle is in the pouring position to convey the ladle along said path with the mold during the filling of each mold.

9. A device for transferring molten non-ferrous easily oxidizable metal, comprising a substantially U-shaped continuously unbroken tube of glass having a long body adapted to extend from a crucible to a horizontally spaced ladle and legs at angles to said body open only at ends adapted to be immersed in bodies of metal in the crucible and ladle, respectively, said tube enclosed except at end portions of said legs within a jacket carrying electrical radiant heating elements spaced from the tube to heat said tube.

10. A device for transferring molten non-ferrous easily oxidizable metal, comprising a substantially U-shaped continuously unbroken tube of glass having a long body adapted to extend from a crucible to a horizontally spaced ladle and legs at angles to said body open only at ends adapted to be immersed in bodies of metal in the crucible and ladle, respectively, said tube enclosed except at end portions of said legs within a jacket carrying electrical radiant heating elements spaced from the tube to heat said tube, and housing boots forming a chamber open at the top to receive and carrying electrical radiant heating element about said chamber to heat said end portions when said tube is not in Working position.

WILLIAM H. FINKELDEY. FLETCHER R. EDES.

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